The present invention relates to a variable-reluctance accelerometer, in particular, though not exclusively, for measuring vertical acceleration of a point on a moving system, e.g. a vehicle.
Numerous types of accelerometers are currently available on the market. In particular, vertical acceleration is known to be measured using a body of a given weight resting on a flexible horizontal blade firmly connected to another body the acceleration of which is to be measured. Should the blade and the body resting on it be both stationary or moving uniformly, the force exerted by the body on the blade is no more than the weight of the body itself. If, on the other hand, both move vertically in varying manner, the blade is also subjected to the force deriving from the mass of the body multiplied by its acceleration, and is therefore deformed. Acceleration may be evaluated by measuring certain effects deriving from deformation of the blade: for example, if the latter consists of a microphone diaphragm, deformation results in a variation of microphone current, which is easily measurable.
Though sufficiently prompt-acting, i.e. capable of giving an accurate indication of even rapidly varying acceleration, a measuring method of the aforementioned type presents a number of drawabacks, one of which is undoubtedly the generation of so-called spurious signals, even in the presence of zero acceleration.
Other types of accelerometers are also known, but these fail to provide fully for the rapid response, reliability and linearity required for specific applications, such as the control of actuators (e.g. suspension regulating devices) used on motor vehicles.